Luminescent material and preparation method thereof

Abstract

The present application relates to a luminescent material and a preparation method thereof. The luminescent material having a chemical formula of M1-x-y-zNbO3:xPr,yEr, where M is alkali metal element, 0.001≤x≤0.05, 0.001≤y≤0.1, and −0.05≤z≤0.05. The luminescent material is a dual-lifetime (fluorescence and long-lasting luminescence) and colorful (red, orange, yellow, yellow green and green) renewable luminescent material that respond to multiple stimulation (heat, force and light), and has a characteristic of multidimensional identifiability such as excitation mode, luminescence lifetime and luminescence color.

What is claimed is: 
     
       1. A luminescent material having a chemical formula of M 1-x-y-z NbO 3 :xPr,yEr, where M is one or two of alkali metal elements Li and Na, and 0.001≤x≤0.05, 0.001≤y≤0.1 and −0.05≤z≤0.05, wherein:
 emission lights of the luminescent material exhibit two kinds of lifetimes: fluorescence and long-lasting luminescence; the fluorescence disappears immediately once excitation is stopped, while the long-lasting luminescence will be lasting after the excitation is stopped; 
 the luminescent material has long-lasting luminescence characteristic at room temperature; the long-lasting luminescence disappears by cooling, and reappears when the temperature rises again; 
 the luminescent material is capable of emitting mechanoluminescence under mechanical stimulation, and an intensity of the mechanoluminescence is directly proportional to an intensity of applied stress; 
 emission light of the luminescent material is color-tunable luminescence among red, orange, yellow, yellow green and green; under temperature stimulation and mechanical stimulation, the luminescence is red and has a wavelength of 580 nm to 650 nm; under irradiation of near-infrared light having a wavelength of 980 nm, the luminescence is green and has a wavelength of 520 nm to 570 nm; under irradiation of ultraviolet light having a wavelength of 360 nm to 379 nm, the luminescence has a continuously tunable color in red-orange-yellow-yellow green-green according to selectivity of irradiation wavelength; and a tunable wavelength of the luminescence ranges from 520 nm to 650 nm. 
 
     
     
       2. The luminescent material of  claim 1 , wherein, 0.003≤x≤0.03, 0.003≤y≤0.08, and −0.05≤z≤0.03. 
     
     
       3. The luminescent material of  claim 1 , wherein, the long-lasing luminescence of the luminescent material is capable of being repeatedly excited by irradiation of light having a wavelength of 300 nm to 500 nm. 
     
     
       4. A preparation method for the luminescent material of  claim 1 , wherein,
 the luminescent material is prepared by a solid phase synthesis method in an air environment and the preparation method comprises the following steps: 
 a) separately weighing an alkali metal raw material, an Nb raw material, a Pr raw material and an Er raw material in a stoichiometric ratio of elements, adding deionized water or absolute ethyl alcohol, fully grinding and drying to obtain mixed powder; 
 b) pre-sintering the mixed powder in the air, and cooling to obtain a cooled product; 
 c) grinding and uniformly mixing the cooled product, and calcining the cooled product in the air to obtain a calcined product; and 
 d) cooling the calcined product and grinding into powder to obtain the luminescent material. 
 
     
     
       5. The preparation method of  claim 4 , wherein, the alkaline metal raw material comprises one of or a combination of two or more of carbonates, oxides, sulfides, halides and peroxides of alkaline metal elements; the Nb raw material comprises one or two of oxides and chlorides of Nb; the Pr raw material comprises one of or a combination of two or more of oxides, nitrates and carbonates of Pr; and, the Er raw material comprises one of or a combination of two or more of oxides, nitrates and carbonates of Er. 
     
     
       6. The preparation method of  claim 4 , wherein, in the step b), a temperature for the pre-sintering is 700° C. to 950° C., and a time for the pre-sintering is 3 to 6 hours. 
     
     
       7. The preparation method of  claim 4 , wherein, in the step c), a temperature for the calcining is 950° C. to 1400° C., and a time for the calcining is 3 to 8 hours.